In modern motor vehicles there is always present an air-conditioning system, which is designed to condition the passenger compartment introducing into the passenger compartment itself air at the temperature desired by the user. For this purpose, the air-conditioning system comprises a unit for treatment of the air, which is designed to heat or cool the air that is subsequently introduced into the passenger compartment by a series of ventilation outlets made in the passenger compartment itself.
Normally, inside the passenger compartment, the ventilation outlets are arranged at different levels so as to enable introduction of the air into different areas of the passenger compartment itself. In particular, there are by now always present top ventilation outlets designed to direct air towards the internal wall of the windscreen, intermediate ventilation outlets designed to direct the air towards the driver's body and the body of the passenger occupying the front seat, and bottom ventilation outlets designed to direct the air towards the feet of the driver and of the passenger occupying the front seat. Typically, only the intermediate ventilation outlets are mobile so as to enable regulation of the direction of the air introduced into the passenger compartment, whilst the top and bottom ventilation outlets are fixed and do not enable regulation of the direction of the air introduced into the passenger compartment.